Improvement in machines for bending sheet metals



. GRTN.

auhines for Bending Sheet-Nieuw.

NO. 134,375. W Patented Dec. 31,1872. lm-Im Am" JAMEs cosmos, or New ronk, n. Y.

Specification forming part of Letters Patent No. 134,3?6, dated December 31, 1872.

.To all whom t may concern:

Be it known that I, JAMES GORTON, sheetmetal-'cornice manufacturer, of New York city, in the State of New York, have invented certain Improvements in Machines for Folding and Bending Sheet Metal, of which the following is a specification:

The machine maybe operated by power with suitable connections; but is more especially intended for being operated by hand, and used to bend the galvanized sheet-iron employed in the manufacture of eornices of the thickness of about No. 27 Birmingham gage; but it may be used for bending metals of greater or less thickness, and for other purposes.

rIhe metal for cornices is usually manufactured in sheets about seven feet by two feet. The size and thickness are such as to render it impracticable to bend it at right angles by machines made on the plan of the ordinary tinners tools--in other words, the stiffnessof the metal springs the machine so much that the ordinary hinges located beyond the edges of the work are not sufficien to resist it.

I find that hinges of a construction analogous to the ordinary hinges of doors may be distributed at points (or made continuous) along the whole line of the joint, and have devised a construction in which such hinges are `placed close to the line of the bend, so that the machine is stifi'ened and braced throughout, and the work is folded or bent at a right angle with great perfection.

I have introduced several other improvements which are important in connection with the above.

The following is a description of what I consider the best means of carrying out the invention.

The accompanying drawing forms a part of this specification.

Figure 1 is a front view of the machine in an open condition. Fig. 2 is a corresponding end elevation. In both these figures the clamping-jaw is open, adapted to deliver orreceive the work, and the bender is down out of the way. in both iguresalso an additional hinged piece, which works on the front of the bender, is represented as down out of the way.

Fig. 3 is a cross-section through the machine in the closed condition. Fig. 4. is a plan view representing the machine in the same condition. In both these Figs. 3 and 4 the clamping part is represented as closed, so as to firmly hold a portion ofthe sheet metal, and the bender is up in the position which it is made to assume to induce a sharp bend along a desired line. It bends the free portion of the metal in front of the clamp directly upward. In both these Figs. 3 and 4 the additional folding piece on the front of the bender is represented as up in the position for use.

Similar letters of reference indicate like parts in all the figures.

A is a rigid framing, of cast-iron or other suitable material, supported on legs at a convenient height above the iioor, and Bis a movable piece mounted close above it, and raised and lowered by means of stout hand-screws D D, which play through swiveling-nuts b1 b2. The arrangement allows the clamping-pieceB to be raised and lowered in a position parallel to the upper surface of the bed A by operating both screws at the same time; or, instead thereof, the screw at one end having been carefully adjusted in the best position, the clamping-piece B may be raised and lowered sufficiently by operating one screw alone. E is a stout folding piece, which I call the bender. It turns on a series of hinges or knuckles, e, of small diameter, mounted close to the line of bending, and a little within the line or under the edge of the clamping-piece B.

What I esteem the best position for the hinge is that represented where the hinges are just a semi-diameter under the edge of the clamping-piece B. This I iind, by calculation and by trial, gives the least scraping effect 0n the metal in effectin g the bending.

The bender E is formed with a shoulder, E', which is nicely finished in a planing-machine or otherwise, and is adapted to match squarely against the front edge of the clampingpiece B, allowing only for the ordinary thickness of the sheet metal between them. On

. raising the bender E E', which I will designate by the single letter E, to the position shown in Fig. 3, all of the sheet metal which projects forward of the front edge of the clamping-piece B is bent upward at right angles to the portion within the clamp. G G are long pawls fixed upon a single shaft, g, carried on arms projecting downward from the bender E. When the bender is raised the pawls G G drop a little and take hold with their shouldered end, as represented in Fig. 3, of the keepers or embracing-pieces a. In this position they hold the bender tightly up against the bent portion of the metal. When it is desired to' drop the bender into the position shown in Fig. 2, it is necessary simply to turn the shaft g a little so as to lift the pawls G G, and thus set them at liberty.

In making cornices there are many folds or abrupt right-angled bends of the metal in different directions. After each bend the metal usually requires to be drawn out from under the clamp B and turned over, so that each bend will be in the opposite direction from the one whichprecedes it. j

It will be understood that the portions already bent will be always in the free metal in front of the machine. In other Words, the fresh plate of metal is first pushed inward through the clamps to nearly its full extent, and a small portion only bent upward, and at each succeeding operation the plate is placed further and further forward, until at last the clamps receive only a smallportion of the back edge of the metal.

Some ornaments require a nice rounding or curvature ofthe metal along some portions in stead of a sharp bend. To accomplish this I mount an additional hinged part, H, folding on the front of the bender E, and connected thereto by bent arms h1 h2 h3 h4, which turn ou hinges 7L fixed on the bender E in the position represented. The rounded or effective portion of this additional piece H may be changed at will, so as to substitute a piece of greater or less diameter, according to the curvature desired for the particular ornament required.

lt will be understood that there are usually required a large number of sheets all bent just alike. When that series of sheets is finished the piece H may be removed and another of greater or less radius may be substituted. The position of the hinge h is so far back under the bender E that, so soon as the bender is dropped into its nearly vertical position, as represented in Fig. 2, the gravity of the adtional folding-piece H h causes it to open by turning on It as an axis, dropping into the po-. 4sition shown in dotted lines in Fig. 2. The

boxes or nuts b1 b2 being mounted on stout trunnions, and capable of swiveling freely, allow the clamping-piece B to be raised to a quite oblique position, if desired.

When only one man is operating the machine it-much facilitates the labor to dispense with raising both ends of the clamp B, and raise only one.

Though I have referred to the bend as beA ing made exactly square, it is preferable to bend the material a little beyond a mathcmatically-exact right angle, to allow for the slight straightening of the bend due to the elasticity of the matter. Y

It will be observed that the construction causes the bender, in effect, to strike a blow upon the turned-up material at themoment that the bend is completed. The gradual bending of the metal at the angle and the forcible compression of it in this manner by percussion seem to favor the grain of the metal, and induce less cracking along the exterior angle at te bend than with any ordinary amount of ben It is possible, and I esteem it likely, that the fact that the metal is drawn together by the frictional action of the bender against it contributes to prevent the cracking open of the material.

It will be observed that the motion of the acting part of the bender, While nearly coinciA dent with that of the metal with which it is in contact, does not quite correspond therewith. It slides in a direction toward the bend, thus tending, by all the force due to the friction,to draw the metal together. It tends to make the bend more by the compression of the inside than by the extension of the outside .of the metal. It will be observed that this is a desirable condition.

The pawls G G hold up the bender E very firmly during the period while the additional folding-piece H is in use. 'v

To curve the metal around the piece H, the metal is first bent upward by theelevation of the bender, and it is held there tightly by the pawls G. Then the piece H, being' raised into the proper position, it is held .very firmly with its upper edge coincident with the upper edge of the bender. Now, the sheet lmetal may be bent forward either by taking hold with the hands, or, if necessary, by assisting it with light blows with a mallet; and, un'- like ordinary devices for this purpose, from the firmness with which the sheet is held by the bender E in the clamp-piece B, and also the firmness with which the piece H is held up in its position by the several arms h1. h2, &c., the curvature is produced with great per fection.

The fact that the shaft g extends along the whole front of the machine allows the pawls to be lifted perfectly from any position. hand may grasp the shaft g at the middle'or near either end, and will be effective in lift ing the bender E; and, also, by applying a twisting force to the shaft g, will be-effectivo in lifting the pawls G to allow the bender to descend.

I claim as my inventionl. The hinged stop or stops G g, in com- The i ushaft g, and with the folding part H stify connected by the arms h1 h2 to the hinge or hinges h, all as herein specied.

In testimony whereof I have hereunto set my hand this 22d day of August, 1872, in the presence of two subscribing Witnesses.

JAMES GORTQN.

Witnesses WM. G. DEY, ARNOLD HRMANN. 

